The goal of this research program is to understand the acquisition of motor skills in infancy and early childhood. Specifically, this research is concerned with the dual-nature of skill: how children learn to become both stable in their performance and flexible in their abilities to engage in new tasks. The studies are informed by a dynamic systems perspective and address skill development in terms of dynamics tested and coupled over levels and time scales. This theoretical approach focuses on the multiple, interacting factors that lead to movement. Here we especially consider how perception, motor memory, and task intersect in producing movements of eyes and head, and manual actions of varying complexities. Studies look at changes in real and developmental time and include empirical research, model simulation and robotics. Specific Aim 1 is based on a new model of infant visual habituation. In six experiments, we manipulate the metric parameters contributing to infants' development of visual attention. In Specific Aim 2 we study the dynamics of action memories for simple reaching with hands and with feed in infants and toddlers, and how those memories interact with visual attention. Specific Aim 3 is to study the dynamics of complex motor actions. Infants and toddlers are tested with toys of varying complexity to understand how recent and longer-term experience affect their tendencies to repeat or switch to new actions. In Specific Aim 4 we implement these theoretical models in an autonomous robot to further explore mechanisms of real time behavior and its developmental course. Specific Aim 5 is to continue experiments on infant limb perturbations currently funded and Specific Aim 6 to write a book on development of embodied cognition based on these and previous experimental and modeling work. These studies impact upon our understanding of basic mechanisms of skill development and continue to contribute new theories of clinical intervention in pediatric physical and occupational therapy.